Heat exchanger of heat-source-side unit and heat pump apparatus including the heat exchanger

ABSTRACT

A heat exchanger of a heat-source-side unit includes: a heat exchange unit where heat transfer tube groups, each of which includes a plurality of heat transfer tubes arranged in a vertical direction, are provided in an air passage direction in at least three or more rows; a liquid-side connecting pipe forming an inlet or an outlet for refrigerant in a liquid phase or in a gas-liquid two phase; and a distributor configured to distribute the refrigerant to a plurality of refrigerant flow passages forming the heat exchange unit. In at least two heat transfer tube groups of the heat transfer tube groups of the heat exchange unit, the liquid-side connecting pipe is connected to one end of a heat transfer tube located at least at a lowermost portion of each of the two heat transfer tube groups and the distributor is connected to the other end of the heat transfer tube.

TECHNICAL FIELD

The present disclosure relates to a heat exchanger of a heat-source-side unit that can suppress the growth of ice frozen at the lowermost portion of a heat exchange unit, and to a heat pump apparatus including the heat exchanger.

BACKGROUND ART

A heat-source-side unit of a heat pump apparatus includes a heat exchanger that causes heat exchange between air and refrigerant. The heat exchanger includes heat exchange units each of which includes a large number of heat transfer tubes. In general, the heat exchange units are disposed on a windward side and a leeward side, thus being arranged in two rows. However, recently, to increase heat exchange efficiency, a configuration is used where the heat exchange units are arranged in an air passage direction in three or more rows.

When the heat-source-side unit of the heat pump apparatus is used as an evaporator, the evaporating temperature of refrigerant becomes lower than the temperature of surrounding air and hence, moisture in the air forms condensation on the surface of fins, and condensation water flows through the fins and collects in the lower portion of the heat exchanger and on the bottom plate of a housing. When outside air drops below freezing point, the condensation water collecting in the lower portion of the heat exchanger and on the bottom plate of the housing may freeze. The frozen ice may grow with time, thus damaging the lower portion of the heat exchanger. Therefore, it is desirable that the heat-source-side unit have a configuration that can suppress the growth of ice by melting the frozen ice.

For example, a heat exchanger of a heat-source-side unit of a refrigerating device disclosed in Patent Literature 1 includes a large number of fins, a plurality of first heat transfer tubes, which are arranged in the vertical direction and form the first row, a plurality of second heat transfer tubes, which are arranged in the vertical direction and form the second row, a plurality of third heat transfer tubes, which are arranged in the vertical direction and form the third row, a liquid-side connecting pipe, a gas-side connecting pipe, and a flow divider configured to divide the flow of refrigerant. The first heat transfer tubes are located on the windward side of the flow of outside air. The third heat transfer tubes are located on the leeward side of the flow of outside air. The second heat transfer tubes are located between the first heat transfer tubes and the third heat transfer tubes.

The first heat transfer tube located at the lowermost portion of the first row, the second heat transfer tube located at the lowermost portion of the second row, and the third heat transfer tube located at the lowermost portion of the third row are connected with each other to form a first flow passage. The liquid-side connecting pipe is connected to the first heat transfer tube located at the lowermost portion of the first row. The flow divider is connected to the third heat transfer tube located at the lowermost portion of the third row. In the case where the heat exchanger serves as an evaporator, refrigerant at a relatively high temperature flows into the first heat transfer tube from the liquid-side connecting pipe, passes through the second heat transfer tube and the third heat transfer tube, and then flows into the flow divider. The flow divider divides, into four branch pipes, the flow of refrigerant that flows into the first flow passage from the liquid-side connecting pipe and then flows out from the first flow passage. Remaining first heat transfer tubes, second heat transfer tubes, and third heat transfer tubes, that is, heat transfer tubes other than the first heat transfer tube, the second heat transfer tube, and the third heat transfer tube forming the first flow passage, form four branch flow passages through which refrigerant that flows out from the plurality of respective branch pipes flows. Refrigerant that flows out from the four branch flow passages flows into a gas-side header to merge together and, thereafter, flows out to the gas-side connecting pipe.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2015-141009

SUMMARY OF INVENTION Technical Problem

In the heat exchanger disclosed in the above-mentioned Patent Literature 1, the first heat transfer tube located at the lowermost portion of the first row, the second heat transfer tube located at the lowermost portion of the second row, and the third heat transfer tube located at the lowermost portion of the third row are connected with each other to form one flow passage. Refrigerant at a relatively high temperature flows into the first heat transfer tube from the liquid-side connecting pipe, passes through the second heat transfer tube and the third heat transfer tube, and then flows into the flow divider. In general, when the temperature of refrigerant flowing through the heat transfer tube located at the lowermost portion of the heat exchanger is higher than 0° C., it is possible to suppress freezing of the heat exchanger. However, in this heat exchanger, the temperature of refrigerant reduces due to pressure loss in pipes and heat exchange when refrigerant at a relatively high temperature flows into the first heat transfer tube from the liquid-side connecting pipe and then flows into the third heat transfer tube from the first heat transfer tube. Accordingly, there is a possibility that a sufficient effect for melting ice cannot be obtained.

The present disclosure has been made to solve the above-mentioned problems, and it is an object of the present disclosure to provide a heat exchanger of a heat-source-side unit that can suppress the growth of ice by melting the ice frozen at the lowermost portion of the heat exchange unit when the heat exchanger serves as an evaporator, and to provide a heat pump apparatus including the heat exchanger. Solution to Problem

A heat exchanger of a heat-source-side unit according to one embodiment of the present disclosure includes: a heat exchange unit where heat transfer tube groups, each of which includes a plurality of heat transfer tubes arranged in a vertical direction, are provided in an air passage direction in at least three or more rows; a liquid-side connecting pipe forming an inlet or an outlet for refrigerant in a liquid phase or in a gas-liquid two phase; and a distributor configured to distribute the refrigerant to a plurality of refrigerant flow passages forming the heat exchange unit, wherein in at least two heat transfer tube groups of the heat transfer tube groups of the heat exchange unit, the liquid-side connecting pipe is connected to one end of a heat transfer tube located at least at a lowermost portion of each of the two heat transfer tube groups and the distributor is connected to the other end of the heat transfer tube.

A heat pump apparatus according to another embodiment of the present disclosure includes a refrigerant circuit through which refrigerant cycles, the refrigerant circuit being formed by connecting a compressor, a load-side heat exchanger, an expansion mechanism, and the above-mentioned heat exchanger of the heat-source-side unit in this order by a pipe.

Advantageous Effects of Invention

In the heat exchanger of the heat-source-side unit and the heat pump apparatus including the heat exchanger of the embodiments of the present disclosure, in at least two heat transfer tube groups, the liquid-side connecting pipe is connected to one end of the heat transfer tube located at least at the lowermost portion of each of the two heat transfer tube groups and the distributor is connected to the other end of the heat transfer tube. Therefore, when the heat exchanger serves as an evaporator, it is possible to cause refrigerant at a relatively high temperature, which flows out from the liquid-side connecting pipe, to flow into the respective heat transfer tubes located at the lowermost portions. Accordingly, it is possible to suppress the growth of ice frozen at the lowermost portion of the heat exchange unit.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a refrigerant circuit diagram of a heat pump apparatus according to Embodiment 1.

FIG. 2 is a perspective view showing a heat-source-side unit of the heat pump apparatus according to Embodiment 1 with some components omitted.

FIG. 3 is an explanatory view schematically showing a heat-source-side heat exchanger of the heat pump apparatus according to Embodiment 1.

FIG. 4 is an explanatory view schematically showing a heat-source-side heat exchanger of a heat pump apparatus according to Embodiment 2.

DESCRIPTION OF EMBODIMENTS

Hereinafter, Embodiments of the present disclosure will be described with reference to drawings. In the respective drawings, identical or corresponding components are given the same reference symbols, and the description of such components is omitted or simplified when appropriate. The shapes, the sizes, the arrangement, and the like of the components described in the respective drawings may be suitably changed.

Embodiment 1

FIG. 1 is a refrigerant circuit diagram of a heat pump apparatus according to Embodiment 1. FIG. 2 is a perspective view showing a heat-source-side unit of the heat pump apparatus according to Embodiment 1 with some components omitted.

As shown in FIG. 1 , a heat pump apparatus 100 according to Embodiment 1 includes a heat-source-side unit 200 and a load-side unit 300. The heat pump apparatus 100 is used for performing air conditioning or for supplying hot water, for example. The heat pump apparatus 100 includes a refrigerant circuit 400 through which refrigerant cycles. The refrigerant circuit 400 is formed by connecting a compressor 10, a flow switching device 11, a heat-source-side heat exchanger 12, an expansion mechanism 13, and a load-side heat exchanger 14 in this order by a gas pipe 15 and a liquid pipe 16. The compressor 10, the flow switching device 11, the heat-source-side heat exchanger 12, and the expansion mechanism 13 are provided to the heat-source-side unit 200. The load-side heat exchanger 14 is provided to the load-side unit 300.

In the heat-source-side unit 200, as shown in FIG. 1 and FIG. 2 , the compressor 10, the flow switching device 11, the heat-source-side heat exchanger 12, and the expansion mechanism 13 are housed in a housing 201 forming an outer shell. The compressor 10 and the heat-source-side heat exchanger 12 are provided to the upper surface of a bottom plate 201 a of the housing 201.

The compressor 10 compresses sucked refrigerant into a high temperature and high pressure state, and discharges the refrigerant. For example, the compressor 10 may be a positive-displacement compressor configured to be able to vary an operating capacity and driven by a motor controlled by an inverter.

The flow switching device 11 is a four-way valve, for example, and has a function of switching a flow passage for refrigerant. Specifically, when the heat-source-side heat exchanger 12 serves as a condenser, the flow switching device 11 switches the refrigerant flow passage such that the refrigerant discharge side of the compressor 10 is connected with the gas side of the heat-source-side heat exchanger 12 and the refrigerant suction side of the compressor 10 is connected with the gas side of the load-side heat exchanger 14. When the heat-source-side heat exchanger 12 serves as an evaporator, the flow switching device 11 switches the refrigerant flow passage such that the refrigerant discharge side of the compressor 10 is connected with the gas side of the load-side heat exchanger 14 and the refrigerant suction side of the compressor 10 is connected with the gas side of the heat-source-side heat exchanger 12. The flow switching device 11 may be formed by combining two-way valves or three-way valves, for example.

During a cooling operation, for example, the heat-source-side heat exchanger 12 serves as a condenser, thus causing refrigerant discharged from the compressor 10 to exchange heat with air. During a heating operation, for example, the heat-source-side heat exchanger 12 serves as an evaporator, thus causing refrigerant that flows out from the expansion mechanism 13 to exchange heat with air. The heat-source-side heat exchanger 12 sucks outdoor air by using fans, causes the air to exchange heat with refrigerant, and then discharges the air to the outside of a room.

The expansion mechanism 13 causes refrigerant flowing through the refrigerant circuit to expand by reducing the pressure of the refrigerant. For example, the expansion mechanism 13 may be an electronic expansion valve where an opening degree is variably controlled.

During the cooling operation, for example, the load-side heat exchanger 14 serves as an evaporator, thus causing refrigerant that flows out from the expansion mechanism 13 to exchange heat with air. During the heating operation, for example, the load-side heat exchanger 14 serves as a condenser, thus causing refrigerant discharged from the compressor 10 to exchange heat with air. The load-side heat exchanger 14 sucks indoor air by using the fans, causes the air to exchange heat with refrigerant, and then supplies the air to the inside of the room.

Next, the configuration of the heat-source-side heat exchanger 12 will be described based on FIG. 3 while referring to FIG. 2 . FIG. 3 is an explanatory view schematically showing the heat-source-side heat exchanger of the heat pump apparatus according to Embodiment 1. An outline arrow in FIG. 3 shows an air passage direction X.

As shown in FIG. 3 , the heat-source-side heat exchanger 12 includes a heat exchange unit 1, a distributor 5, and a liquid-side connecting pipe 6. In the heat exchange unit 1, heat transfer tube groups (3A to 3C), each of which includes a plurality of heat transfer tubes 3 arranged in the vertical direction, are provided in the air passage direction X in three rows. The distributor 5 distributes refrigerant to a plurality of refrigerant flow passages (4 a to 4 c) forming the heat exchange unit 1. The liquid-side connecting pipe 6 forms an inlet or an outlet for refrigerant in a liquid phase or in a gas-liquid two phase.

As shown in FIG. 2 and FIG. 3 , the heat exchange unit 1 is of a fin tube type (cross fin type) that includes a plurality of fins 2 and the heat transfer tube groups (3A to 3C), each of which includes the plurality of heat transfer tubes 3 arranged in the vertical direction. The fins 2 are made of a metal material, such as an aluminum alloy, and are in contact with the heat transfer tubes 3 to increase a heat transfer area. The fins 2 are arranged parallel to each other at intervals in a direction substantially orthogonal to the air passage direction X such that plate-like surfaces of the fins 2 are substantially parallel to each other.

The heat transfer tube groups (3A to 3C) include a first-row heat transfer tube group 3A, a second-row heat transfer tube group 3B, and a third-row heat transfer tube group 3C arranged in this order from the leeward side, and are arranged along the air passage direction X in three rows. The first-row heat transfer tube group 3A includes a plurality of heat transfer tubes (30 a to 30 e) arranged in the vertical direction. The second-row heat transfer tube group 3B includes a plurality of heat transfer tubes (31 a to 31 e) arranged in the vertical direction. The third-row heat transfer tube group 3C includes a plurality of heat transfer tubes (32 a to 32 e) arranged in the vertical direction. The heat transfer tube groups (3A to 3C) may be provided in the air passage direction X in three or more rows. For the sake of convenience of illustration, only five heat transfer tubes in each row are shown. However, the actual heat transfer tube group includes five or more heat transfer tubes.

Each heat transfer tube 3 is made of a metal material, such as an aluminum alloy, and a flow passage, through which refrigerant flows, is formed in the heat transfer tube 3. In the heat transfer tube groups (3A to 3C), the liquid-side connecting pipe 6 is connected to one end of the heat transfer tube 30 a and to one end of the heat transfer tube 32 a and the distributor 5 is connected to the other end of the heat transfer tube 30 a and to the other end of the heat transfer tube 32 a. The heat transfer tube 30 a is located at the lowermost portion of the first-row heat transfer tube group 3A. The heat transfer tube 32 a is located at the lowermost portion of the third-row heat transfer tube group 3C. In the example shown in the drawing, the heat transfer tube 30 a, which is located at the lowermost portion of the first-row heat transfer tube group 3A, is connected with the heat transfer tube 31 a, which is located at the lowermost portion of the second-row heat transfer tube group 3B, so that the liquid-side connecting pipe 6 is connected to the heat transfer tube 30 a, and the distributor 5 is connected to the heat transfer tube 31 a. In the heat transfer tube 32 a, which is located at the lowermost portion of the third-row heat transfer tube group 3C, the liquid-side connecting pipe 6 is connected to one end of the heat transfer tube 32 a and the distributor 5 is connected to the other end of the heat transfer tube 32 a.

In the heat exchange unit 1, except for the heat transfer tubes (30 a, 31 a, 32 a) located at the lowermost portions of the heat transfer tube groups (3A to 3C), heat transfer tubes in adjacent rows in the air passage direction X are connected with each other, thus forming a plurality of refrigerant flow passages (4 a to 4 c) arranged in the vertical direction. In the respective refrigerant flow passages (4 a to 4 c), respective heat transfer tubes (32 b to 32 e) in the third-row heat transfer tube group 3C are connected to the distributor 5, and respective heat transfer tubes (30 b to 30 e) in the first-row heat transfer tube group 3A are connected to the gas pipe 15. The respective heat transfer tubes (30 b to 30 e) in the first-row heat transfer tube group 3A may be connected with the gas pipe 15 via gas connecting pipes.

It is sufficient for the heat exchange unit 1 to have a configuration where, in two heat transfer tube groups (3A to 3C), the liquid-side connecting pipe 6 is connected to one end of the heat transfer tube (30 a to 32 a) located at least at the lowermost portion of each of the two heat transfer tube groups (3A to 3C), and the distributor 5 is connected to the other end of the heat transfer tube (30 a to 32 a). The heat exchange unit 1 is not limited to the configuration shown in the drawing. Although not shown in the drawing, for example, the heat exchange unit 1 may be configured such that the liquid-side connecting pipe 6 is connected to one end of the heat transfer tube 30 a, which is located at the lowermost portion of the first-row heat transfer tube group 3A, and to one end of the heat transfer tube 30 b, which is located at the lowermost portion of the second-row heat transfer tube group 3B, and the distributor 5 is connected to the other end of the heat transfer tube 30 a and to the other end of the heat transfer tube 30 b. It is not always necessary to connect the heat transfer tube 30 a, which is located at the lowermost portion of the first-row heat transfer tube group 3A, with the heat transfer tube 31 a, which is located at the lowermost portion of the second-row heat transfer tube group 3B. A configuration may be adopted where the liquid-side connecting pipe 6 is connected to one end of the heat transfer tube 30 a and the distributor 5 is connected to the other end of the heat transfer tube 30 a.

Although not shown in the drawing, the heat exchange unit 1 may be configured such that the liquid-side connecting pipe 6 and the distributor 5 are connected to each of the heat transfer tubes (30 a, 31 a, 32 a), which are located at the lowermost portions, and to the heat transfer tubes (30 b, 31 b, 32 b), which are located at the second lowermost portions, or to the heat transfer tubes (30 c, 31 c, 32 c), which are located at the third lowermost portions. Alternatively, the heat exchange unit 1 may be configured such that the liquid-side connecting pipe 6 and the distributor 5 are connected to each of all heat transfer tubes (30 a to 30 c, 31 a to 31 c, 32 a to 32 c), which are located at the lowermost portions, the second lowermost portions, and the third lowermost portions. In this case, a configuration may be adopted where the liquid-side connecting pipe 6 and the distributor 5 are connected to each heat transfer tube, or a configuration may be adopted where heat transfer tubes disposed adjacent to each other in the vertical direction or in the air passage direction X are connected with each other and the liquid-side connecting pipe 6 and the distributor 5 are connected to each set of connected heat transfer tubes. The description has been made for heat transfer tubes located at the second and third lowermost portions. However, the same applies for heat transfer tubes located at the fourth lowermost portions or higher portions.

The liquid-side connecting pipe 6 connects the liquid pipe 16 with the heat transfer tubes (30 a, 32 a). The liquid-side connecting pipe 6 may be a two-branch pipe, for example. The liquid-side connecting pipe 6 may be a portion of the liquid pipe 16, or may be a part separated from the liquid pipe 16.

The distributor 5 includes a distributor body 50, inflow pipes 51, and a plurality of fine pipes 52. The inflow pipes 51 connect the distributor body 50 with the heat transfer tubes (30 a, 32 a). The plurality of respective fine pipes 52 are connected to the distributor body 50. Each fine pipe 52 may be a capillary tube, for example. Each of the fine pipes 52 is connected to one end of each of the heat transfer tubes (32 b to 32 e), which are heat transfer tubes that do not include the lowermost heat transfer tube of the heat transfer tubes (32 a to 32 e) in the third-row heat transfer tube group 3C. Refrigerant flows into the distributor body 50 via the inflow pipe 51 and is then distributed to the respective fine pipes 52 by the distributor body 50, thus being reduced in pressure by the fine pipes 52 and, thereafter, flows into the respective refrigerant flow passages (4 a to 4 c). The distributor 5 is not limited to the configuration shown in the drawing. Provided that the distributor 5 can distribute refrigerant to the plurality of refrigerant flow passages (4 a to 4 c) forming the heat exchange unit 1, other mode may be adopted.

In the case where the heat-source-side unit 200 of the heat pump apparatus 100 is used as an evaporator, the evaporating temperature of refrigerant becomes lower than the temperature of surrounding air and hence, moisture in the air forms condensation on the surface of the fins 2, and condensation water flows through the fins 2 and collects in the lower portion of the heat exchanger 12 and on the upper surface of the bottom plate 201 a of the housing 201. When outside air drops below freezing point, condensation water collecting in the lower portion of the heat exchanger 12 and on the upper surface of the bottom plate 201 a of the housing 201 may freeze. The frozen ice may grow with time, thus damaging the lower portion of the heat exchanger 12.

In view of the above, the heat exchanger 12 of the heat-source-side unit 200 according to Embodiment 1 includes the heat exchange unit 1, the liquid-side connecting pipe 6, and the distributor 5. In the heat exchange unit 1, the heat transfer tube groups (3A to 3C), each of which includes the plurality of heat transfer tubes 3 arranged in the vertical direction, are provided in the air passage direction X in at least three or more rows. The liquid-side connecting pipe 6 forms an inlet or an outlet for refrigerant in a liquid phase or in a gas-liquid two phase. The distributor 5 is configured to distribute refrigerant to the plurality of refrigerant flow passages (4 a to 4 c) forming the heat exchange unit 1. In the heat exchange unit 1, in each of at least two heat transfer tube groups (3A, 3C) of the heat transfer tube groups (3A to 3C), the liquid-side connecting pipe 6 is connected to one end of the heat transfer tube (30 a, 31 a, 32 a) located at least at the lowermost portion of the two heat transfer tube group (3A, 3C), and the distributor 5 is connected to the other end of the heat transfer tube (30 a, 31 a, 32 a).

In other words, in the heat exchanger 12 of the heat-source-side unit 200 according to Embodiment 1, when the heat exchanger 12 serves as an evaporator, it is possible to cause refrigerant at a relatively high temperature, which flows out from the liquid-side connecting pipe 6, to flow into the heat transfer tubes (30 a, 31 a, 32 a) located at the lowermost portion of the heat exchange unit 1 before the refrigerant flows into the distributor 5, thus being reduced in pressure by the fine pipes 52. Therefore, in the heat exchanger 12 of the heat-source-side unit 200 according to Embodiment 1, it is possible to cause refrigerant at a relatively high temperature, which flows out from the liquid-side connecting pipe 6, to flow into the heat transfer tubes (30 a, 31 a, 32 a) located at the lowermost portion under the condition of the outside air being below freezing point. Accordingly, melting of ice can be promoted and hence, it is possible to suppress the growth of ice frozen at the lowermost portion of the heat exchange unit 1.

In the heat exchanger 12 of the heat-source-side unit 200 according to Embodiment 1, when the heat exchanger 12 serves as a condenser, refrigerant that passes through the respective refrigerant flow passages (4 a to 4 c) from the gas pipe 15 passes through the heat transfer tubes (30 a, 31 a, 32 a), which are located at the lowermost portion, through the distributor 5 and then flows into the liquid pipe 16. Therefore, it is possible to reduce a subcooling zone and hence, lowering of performance can be suppressed.

Embodiment 2

Next, a heat exchanger 12 of a heat-source-side unit 200 according to Embodiment 2 will be described based on FIG. 4 . FIG. 4 is an explanatory view schematically showing a heat-source-side heat exchanger of a heat pump apparatus according to Embodiment 2. An outline arrow in FIG. 4 shows the air passage direction X. Components substantially equal to the corresponding components of the heat exchanger 12 of the heat-source-side unit 200 described in Embodiment 1 are given the same reference symbols, and the description of such components will be omitted when appropriate.

In the heat exchanger 12 of the heat-source-side unit 200 according to Embodiment 2, the liquid-side connecting pipe 6 is connected to one end of each of the heat transfer tubes (30 a, 31 a, 32 a), which are located at the lowermost portions of the first-row heat transfer tube group 3A, the second-row heat transfer tube group 3B, and the third-row heat transfer tube group 3C, and the distributor 5 is connected to the other end of each of the heat transfer tubes (30 a, 31 a, 32 a). The liquid-side connecting pipe 6 is a three-branch pipe that connects the liquid pipe 16 with the heat transfer tubes (30 a, 31 a, 32 a).

In other words, in the heat-source-side heat exchanger 12, it is possible to cause refrigerant at a relatively high temperature flowing through the liquid-side connecting pipe 6 to directly flow into all of the heat transfer tubes (30 a, 31 a, 32 a), which are located at the lowermost portion. Accordingly, melting of ice can be uniformly promoted over a wide range and hence, freezing of the heat exchange unit 1 can be suppressed.

Although not shown in the drawing, the heat exchange unit 1 may be configured such that the liquid-side connecting pipe 6 and the distributor 5 are connected to each of the heat transfer tubes (30 a, 31 a, 32 a), which are located at the lowermost portions, and to the heat transfer tubes (30 b, 31 b, 32 b), which are located at the second lowermost portions, or the heat transfer tubes (30 c, 31 c, 32 c), which are located at the third lowermost portions. Alternatively, the heat exchange unit 1 may be configured such that the liquid-side connecting pipe 6 and the distributor 5 are connected to all of the heat transfer tubes (30 a to 30 c, 31 a to 31 c, 32 a to 32 c), which are located at the lowermost portions, the second lowermost portions, and the third lowermost portions. In this case, a configuration may be adopted where the liquid-side connecting pipe 6 and the distributor 5 are connected to each heat transfer tube, or a configuration may be adopted where heat transfer tubes disposed adjacent to each other in the vertical direction or in the air passage direction X are connected with each other and the liquid-side connecting pipe 6 and the distributor 5 are connected to each set of connected heat transfer tubes. The description has been made for the heat transfer tubes located at the second and third lowermost portions. However, the same applies for heat transfer tubes located at the fourth lowermost portions or higher portions.

Heretofore, the description has been made for the heat exchanger 12 of the heat-source-side unit 200 and the heat pump apparatus 100 including the heat exchanger 12 based on Embodiments 1 and 2. However, the heat exchanger 12 of the heat-source-side unit 200 and the heat pump apparatus 100 are not limited to the configurations of the above-mentioned Embodiments. For example, the heat exchanger 12 of the heat-source-side unit 200 and the heat pump apparatus 100 are not limited to the above-mentioned components, and may include other components. Further, the heat exchange unit 1 is not limited to the configuration of the fin tube type (cross fin type) shown in the drawing, and other mode may be adopted. In short, the heat exchanger 12 of the heat-source-side unit 200 and the heat pump apparatus 100 include variations to which design changes or applications are regularly added by those who are skilled in the art without departing from the technical concept.

REFERENCE SIGNS LIST

1: heat exchange unit, 2: fin, 3: heat transfer tube, 3A: first-row heat transfer tube group, 3B: second-row heat transfer tube group, 3C: third-row heat transfer tube group, 4 a, 4 b, 4 c: refrigerant flow passage, 5: distributor, 6: liquid-side connecting pipe, 10: compressor, 11: flow switching device, 12: heat-source-side heat exchanger, 13: expansion mechanism, 14: load-side heat exchanger, 15: gas pipe, 16: liquid pipe, 30 a to 30 e: heat transfer tube, 31 a to 31 e: heat transfer tube, 32 a to 32 e: heat transfer tube, 50: distributor body, 51: inflow pipe, 52: fine pipe, 100: heat pump apparatus, 200: heat-source-side unit, 201: housing, 201 a bottom plate, 300: load-side unit, 400: refrigerant circuit. 

1. A heat exchanger of a heat-source-side unit, the heat exchanger comprising: a heat exchange unit where heat transfer tube groups, each of which includes a plurality of heat transfer tubes arranged in a vertical direction, are provided in an air passage direction in at least three or more rows; a liquid-side connecting pipe forming an inlet or an outlet for refrigerant in a liquid phase or in a gas-liquid two phase; and a distributor configured to distribute the refrigerant to a plurality of refrigerant flow passages forming the heat exchange unit, wherein in at least two heat transfer tube groups of the heat transfer tube groups of the heat exchange unit, the liquid-side connecting pipe is connected to one end of a heat transfer tube located at a lowermost portion of each of the two heat transfer tube groups and the distributor is connected to an other end of the heat transfer tube.
 2. The heat exchanger of the heat-source-side unit of claim 1, wherein the heat transfer tube groups include a first-row heat transfer tube group, a second-row heat transfer tube group, and a third-row heat transfer tube group arranged in this order from a leeward side in three rows, and the liquid-side connecting pipe is connected to heat transfer tubes located at lowermost portions of the first-row heat transfer tube group, the second-row heat transfer tube group, and the third-row heat transfer tube group.
 3. The heat exchanger of the heat-source-side unit of claim 1 , wherein the distributor includes a fine pipe connected with the plurality of refrigerant flow passages forming the heat exchange unit.
 4. A heat pump apparatus including a refrigerant circuit through which refrigerant cycles, the refrigerant circuit being formed by connecting a compressor, a load-side heat exchanger, an expansion mechanism, and the heat exchanger of the heat-source-side unit of claim 1 in this order by a pipe. 